Re: [Xen-devel] [PATCH v3 1/2] amd/passthrough: Do not leak domain mappings from do_invalidate_dte()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 09/12/13 18:33, Suravee Suthikulanit wrote:
> On 12/4/2013 11:59 AM, Andrew Cooper wrote:
>> Coverity ID: 1135379
>>
>> As the code stands, the domain mapping will be leaked on each error
>> path.
>>
>> The mapping can be for a much shorter period of time, and all the
>> relevent
>> information can be pulled out at once.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>> CC: Keir Fraser <keir@xxxxxxx>
>> CC: Jan Beulich <JBeulich@xxxxxxxx>
>> CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
>>
>> ---
>>
>> Changes in v3:
>>   * Dont break the pointer arithmatic on gdte
>> ---
>>   xen/drivers/passthrough/amd/iommu_guest.c |    9 ++++-----
>>   1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/xen/drivers/passthrough/amd/iommu_guest.c
>> b/xen/drivers/passthrough/amd/iommu_guest.c
>> index 952600a..c1fa0ff 100644
>> --- a/xen/drivers/passthrough/amd/iommu_guest.c
>> +++ b/xen/drivers/passthrough/amd/iommu_guest.c
>> @@ -430,6 +430,10 @@ static int do_invalidate_dte(struct domain *d,
>> cmd_entry_t *cmd)
>>         gdom_id  = get_domid_from_dte(gdte);
>>       gcr3_gfn = get_guest_cr3_from_dte(gdte);
>> +    glx      = get_glx_from_dte(gdte);
>> +    gv       = get_gv_from_dte(gdte);
>> +
>> +    unmap_domain_page(gdte);
> Shouldn't this be "unmap_domain_page (dte_base)" instead?

Probably should be.

>
>>         /* Do not update host dte before gcr3 has been set */
>>       if ( gcr3_gfn == 0 )
>> @@ -449,11 +453,6 @@ static int do_invalidate_dte(struct domain *d,
>> cmd_entry_t *cmd)
>>           return -ENODEV;
>>       }
>>   -    glx = get_glx_from_dte(gdte);
>> -    gv = get_gv_from_dte(gdte);
>> -
>> -    unmap_domain_page(dte_base);
>> -
>>       /* Setup host device entry */
>>       hdom_id = host_domid(d, gdom_id);
>>       req_id = get_dma_requestor_id(iommu->seg, mbdf);
> Also, the comment saying "/* Read guest dte information */ " should
> probably be moved as well.
>
> Suravee
>

Sure - v4 on its way.

~Andrew

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